Advisory Services

Pharmaceutical Dosage Forms

The following are short descriptions of preparations that may be dispensed i.e prepared or supplied in retail or hospital pharmacy. Those products rarely if ever made extemporaneously are asterisked.

1- Aerosols

Aerosols are suspensions of fine solid or liquid particles in a gas. They are used to apply drugs to the respiratory tract and skin.

The official sprays which are used to treat respiratory conditions are atomised in devices known as atomisers or nebulisers. The former resemble scent sprays while the latter are designed to deliver the fine droplets only. The patient introduces the solution and by applying pressure to a bulb ejects the medicament as a mist suspended in air . If necessary, the use of these devices must be explained to the patient; a common fault is to exhale just as the medicament is being sprayed.

Aerosol Inhalations

An alternative, more modern technique is to pack the drug in a pressurised container. The medicament is dissolved in a solvent or if insoluble, suspended in a propellant. The latter is a liquefied gas that vaporises when a valve is opened and discharges the medicament as a mist or fine dust. For potent drugs such as those used for asthma, the valve includes a metering device that delivers a measured dose. Patients should be warned of the danger from exceeding the prescribed dose.

Pressurised aerosol containers provide good protection from oxidation, light. And where necessary as with sterile dermatological products, microorganisms. They are compact, convenient to carry about and the medicament can be applied quickly, simply and for skin preparations, evenly and without touching painful surfaces. Because filling and sealing require special machinery, pressurised aerosols are available only as proprietary products.


These are fluid or semi-fluid preparations intended for application to the skin. Usually they are suspensions or emulsions. Most of the official preparations are used as antiparasites.


2- Cachets

Enclosure in cachets provides a means of administering nauseous or disagreeable powders in a tasteless form.

Cachets are moulded from rice paper, a material made by pouring a mixture of rice flour and water between two, hot. Polished, revolving cylinders; water evaporates and sheet of wafer is formed.

There are two kinds; 'wet seal', so called because water is used to seal them, and 'dry seal'. The wet seal type consists of two halves, both alike, convex in shape and having a broad flange that is used for sealing . The dry seal type has a shallow cylindrical base and a slightly larger, slip over cap. Both are made in variety of sizes holding from 0.2 to 2 g of a powder of medium density. They are softened by immersion in water for a few seconds and then taken with a drought of water.

3- Capsules

There are two main types of capsules and both are available in a variety of sizes. Like cachets they are useful for unpleasant medicaments.

Hard capsules are for solid medicaments. They consist of a cylindrical body and cap, both with hemispherical ends and are usually made from gelatin and water with added preservatives. Although quite hard, they soften readily and dissolve after swallowing with water.

Soft capsules are for solid , semisolids and liquids. They may be spherical (sometimes very small and known as perles), ovoid, or cylindrical with hemispherical ends. In addition to the ingredients of hard capsules, they contain glycerol which provides flexibility.


A solid dosage form in which the drug is enclosed within a hard or soft soluble container or shell.

Capsule, Delayed release

A coated capsule or more commonly encapsulated granules that may be coated to resist releasing the drug in stomach because the drug will irritate gastric mucosa or gastric fluid will inactivate the drug.

Capsule, Extended release

A capsule that is formulated in such a manner as to make the contained medication available over an extended period following ingestion.

4- Collodions

Collodions are fluid preparations for external use. They are applied with a brush or rod. The vehicle is volatile and evaporates on application to the skin, leaving a flexible, protective film covering the site. The volatile solvents are ether and alcohol, the film producing ingredient is pyroxylin (nitrocellulose) and the substance giving the flexibility is castor oil.

Unmedicated and medicated forms are available; the former are useful for protecting small cuts and abrasions while the latter provide prolonged contact between the skin and the medicament.

5- Creams

These are semisolid emulsions for external use. There are two kinds, aqueous and oily creams, in which the emulsions are oil in water and water in oil respectively. The oil in water type is relatively non-greasy. Creams are a very popular form of external medication.

5- Demulcent

A bland viscous liquid, usually water based, used to coat and soothe damaged or inflamed skin or mucous membranes (Methyl cellulose).

6- Draughts

These are liquid oral preparations of which only one or two rather large doses of the order of 50 ml are prescribed. Each dose is issued in a separate container. Ipecacuanha Emetic Drought, Paediatric, is exceptional; the normal dose is 10 or 15 ml and therefore a multiple dose volume is prescribed.

7- Dusting Powders

These are free flowing, very fine powders for external use.

8- Drops, Oral

A solution, emulsion, or suspension i.e. administered in small volumes, such as drops by means of a suitable device.

9- Ear Drops

Ear drops are solutions of drugs that are instilled into the ear with a dropper.

10- Elixirs

Elixirs are clear, liquid, oral preparations of potent or nauseous drugs. They are pleasantly flavored and usually attractively coloured. In general, they are more stable than mixtures but some require preparation immediately before issue to the patient, by adding a solvent to dry granules.

11- Emulsions

An emulsion is a comparatively pleasant form in which to take an oil. The oil in a very fine state of subdivision, is dispersed in flavoured water, the dispersion being stabilised by the addition of an emulsifying agent.


A dosage form in which one liquid is dispersed into the other in the form of small droplets in the presence of emulsifying agent.

12- Enemas

Enemas are solution, suspensions, or oil in water emulsions of medicaments intended for rectal administration.

13- Expectorant

A drug that increases respiratory tract secretions, lowers their viscosity and promotes removal (Potassium Iodide).

14- Fecal Softener

A drug that promotes defecation by softening the feces.

15- Foam

An emulsion packaged in a pressurized aerosol container that has a fluffy, semisolid consistency when dispensed.

                                16- Gargles

Gargles are aqueous solutions used to prevent or treat throat infections. Usually they are dispensed in concentrated form with directions for dilution with warm water before use.

17- Gastroretentive Drug Delivery System

Gastroretentive drug delivery systems are one among such novel drug delivery systems. These are usually intended to deliver the active pharmaceutical ingredient specifically in the gastric region that is preferably in the stomach region. They are based on the mechanism of retention.

18- Gels

Gels are aqueous colloidals suspensions of the hydrated forms of the insoluble medicaments e.g. aluminium hydroxide gel, used as an antacid.

19- Granules

Granules are a comparatively unusual means of administering drugs that possess an unpleasant taste. The drug is mixed with sugar, a flavoring agent and inert adjuncts, moistened to produce a coherent mass, granulated by passage through a sieve and dried. The resultant small irregular particles ranging from 2 to 4 mm in diameter are often supplied in single dose sachets the contents of which are stirred in water before taking.


Prepared agglomerates of powdered materials, may be used per se for the medicinal value of their content or for pharmaceutical purposes as in making tablets.

20- Effervescent Granules

The basis of effervescent granules is a mixture is a mixture of citric and tartaric acids with sodium bicarbonate. Usually a medicament is included and sucrose or saccharin may be added as a sweetening agent.

When the patient dissolves the prescribed dose in water, the acid and bicarbonates react together producing carbonic acid and the preparation is taken during effervescence or immediately afterwards. The carbonated water partly disguises the unpleasant taste of the saline medicaments that are administered in this way.


A dosage form containing ingredients that rapidly release carbon dioxide when in contact with water.

21- Emollient

A topical drug especially an oil or fat used to soften the skin and make it more pliable (cold cream).

22- Implant

A small, sterile solid mass, consisting of a highly purified drug with or without excipients made by compression or molding and put in place by injection or incision.

23- Inhalations

These are liquid preparations consisting of or containing volatile substances. They are used to relieve congestion and inflammation of the respiratory tract. Some are volatile at room temperature and may be inhaled from a handkerchief or a fabric face mask. Others are added to hot but not boiling, water( About 64% is suitable) and the vapour is inhaled for about 10 minutes. This second type of inhalation includes simple solution of medicaments, dissolved in in alcohol or an alcoholic preparation and aqueous dispersions containing light magnesium carbonate to adsorb and diffuse the volatile ingredients.

24- Insufflations

Insufflations are medicated dusting powders that are blown by a insufflator (a device similar to an atomizer)into regions such as nose, throat, body cavities and the ear to which it would be difficult to apply the powder directly. Occasionally, insufflations intended for the nose (e.g. pituitary(posterior lobe)insufflation) are used in the same way as snuff.

25- Injections

Preparations intended for parenteral administration or for constituting or diluting a parenteral article prior to administration.

26- Irrigations

Irrigations are solutions of medicaments used to treat infections of the bladder, vagina and less often the nose. They are administered via a thin, soft, rubber or plastic tube known as catheter (bladder) a vulcanite or plastic pipe (vagina) or a specially designed glass irrigator (nose). Solutions and equipment used for bladder irrigations must be sterile.

27- Jellies

Jellies are transparent or translucent, non-greasy, semi-solid preparations mainly used externally. The gelling agent may be gelatin, or a carbohydrate such as starch, tragacanth, sodium alginate or cellulose derivatives.

28- Linctuses

Linctuses are viscous, liquid, oral preparations that are usually prescribed for relief of cough. They are simple solutions or admixtures containing a high proportion of syrup and sometimes glycerin which as well as giving a sweet taste, have a demulcent effect on the mucous membranes of the throat. The dose is small(5ml) and to ensure prolonged action, should be sipped slowly and swallowed neat.

29- Liniments

Liniments are fluid, semi-fluid or occasionally semi-solid preparations intended for application to the skin. They may be alcoholic or oily solutions or emulsions. Most are massaged into the skin (counter irritant or stimulant type) but some are applied on a warm dressing or with a brush (analgesic or soothing types). Liniments must not be applied to broken skin.

30- Liposomes

An artificial microscopic vesicle consisting of an aqueous core enclosed in one or more  phospholipid layers, used to convey vaccines, drugs, enzymes, or other substances to target cells or organs.

31- Lotions

Lotions are fluid preparations for external application without friction. They are either dabbed on the skin or applied on a suitable dressing and covered with water proof material to reduce evaporation.

32- Lozenges (Troches)

These are solid preparations consisting mainly of sugar and gum, the latter giving hardness and cohesiveness and ensuring slow release of medicament. They are used to medicate the mouth and throat and for the slow administration of indigestion and cough remedies.

33- Mixtures

Mixtures are the most common form of liquid oral preparation. The vehicle is usually aqueous and the medicaments may be in solution or suspension. Generally they are not formulated for a long life and should be freshly or recently prepared and used fairly quickly, e.g. within a mouth.

34- Mouthwashes

These are similar to gargles but are used for oral hygiene and to treat infections of the mouth.

35- Nasal Drops

Nasal drops are solutions of drugs that are instilled into the nose with a dropper. They are usually aqueous because oily drops inhibit movement of cilia in nasal mucosa and if used for long periods, may reach the lungs and cause lipoidal pneumonia.

36- Niosomes

Niosomes are nonionic surfactants based vesicles formed by organization of surfactant macro-molecule as bilayers.


Niosomes are non-ionic surfactant based liposomes. They are mostly formed by cholesterol  incorporation as an excipient. Other excipients can also be used. Niosomes have more penetrating capability than the previous preparations of emulsions.


37- Ointments

Ointments are semi-solid, greasy preparations for application to the skin, rectum and nasal mucosa. The base is usually anhydrous and contains the medicament in solution or suspension.

38- Osmotic Pump

Osmotic Pump is a novel drug delivery system which comprises a first chamber comprising an osmotically active substance, a second chamber arranged to be filled with a solvent, and a semi-permeable barrier separating the first chamber from the second chamber. The semi-permeable barrier is impermeable to the osmotic active substance and permeable to the solvent. The osmotic pump further comprises a position-independent pressure device in fluid communication with the second chamber, wherein the pressure device is arranged for pressurizing the solvent in the second chamber.

39- Paediatric Drops

Occasionally, the children’s dose of a preparation is very small and stability considerations preclude dilution to 5ml. Then the dose is prescribed as a fraction of a milliliter and is given by a calibrated dropper.

40- Paints

Paints are liquids for application to skin or mucosa usually with a soft brush. Skin paints often have a volatile solvent that evaporates quickly to leave a dry or resinous film of medicament. Throat paints are more viscous due to high content of glycerin which being sticky adheres to the affected site and prolong the action of the medicament.

41- Pastes

Pastes are semi-solid preparations for external application that differ from similar products in containing a high proportion of finely powdered medicaments. The base may be anhydrous (liquid or soft paraffin) or water soluble (glycerol or mucilage). Their stiffness makes them useful as protective coatings.

42- Pastilles

Pastilles are solid medicated preparations intended to dissolve slowly in the mouth. They are softer than lozenges and their base is either glycerol and gelatin or acacia and sugar.

43- Pessaries

Pessaries are solid medicated preparations for introduction into the vagina, where they melt or dissolve and exert a local action. They are of two type; moulded pessaries, which are cone shaped and prepared in a similar way to suppositories, and compressed pessaries, which are made in a variety of shapes and like tablets, are prepared by compression.

44- Pills

Pills are oral dosage forms that have largely been replaced by tablets and capsules. They are spherical or less often, ovoid and usually sugar coated.

45- Poultices

Poultices are paste like preparations used externally to reduce inflammation because they retain heat well. After heating, the preparation is spread thickly on a dressing and applied as hot as the patient can bear it, to the affected area.

46- Powders

There are two kinds of powders intended for internal use Bulk powders, which the patient takes with a 5 ml spoon. As this method of dose measurement is imprecise for a powder, only non-potent medicaments, such as indigestion remedies, are prescribed in this form.

Individual powders, which usually contain a potent drug mixed with lactose or other inert diluent. Each dose is separately folded in paper.


An intimate mixture of dry, finely divided drugs or chemicals that may be intended for internal or external use.

47- Premix

A mixture of one or more drug substances with a suitable vehicle.

48- Plaster

A solid or semi-solid mass supplied on a backing material and intended to provide prolonged contact with skin.

49- Rubefacient

A topical drug that induces mild skin irritation with erythema, used as a toughening agent (Rubbing alcohol).

50- Rinse

A solution used to cleanse by flushing.

51- Shampoos

A solution, emulsion or suspension used to clean hair and scalp.

52- Solutions

Solutions are used for many purposes. For some of these sterility is necessary, e.g. parenteral, peritoneal dialysis and anticoagulant solutions, bladder irrigations and dermatological solutions for application to broken surfaces. Unsterile solutions are used orally, either alone or as ingredients of medicines, or externally on unbroken surfaces.


A liquid preparation that contains one or more dissolved chemical substances in a suitable solvent or mixture of miscible solvents, may be oral, topical, otic, ophthalmic.

53- Solution Tablets

These are compressed tablets that are dissolved in water to produce solutions for application to the skin or mucosa. Usually they are uncoated biconvex discs but those containing poisons may be distinctive in shape and colour. They are formulated to dissolve quickly.

54- Sprays

Sprays are preparations of drugs in aqueous, alcoholic or glycerin containing media. They are applied to the mucosa of nose or throat with an atomizer or nebuliser. Oily sprays are best avoided.

55- Suppositories

Suppositories are conical or ovoid, solid preparations for insertion into the rectum where they melt, dissolve or disperse and exert a local or less often, a systemic effect. Their basis is a fat, a wax or a glycerol-gelatin jelly. They weigh 1, 2 or occasionally, 4 g and are usually unmedicated.

In the past, small suppositories known as cones were prescribed for ear infections and long, very narrow forms, called bougies, were used for nasal and urethral infections; these are virtually obsolete.

56- Suspension

A liquid preparation that consists of solid particles dispersed through out a liquid phase in which the particles are not soluble, may be oral, topical, otic, ophthalmic.

57- Syrups

Liquid oral preparations in which the vehicle is a concentrated aqueous solution of sucrose or other sugar used to be called syrups. Now products conforming to this description have been renamed elixirs, if they are clear, or mixtures, if they are suspensions, unless they are not intended for issue to patients, e.g. medicated syrups (used as stock solutions) and flavouring syrups (used as vehicle or flavours). In addition, a few traditional preparations (e.g. syrup of Figs), that are well known to the general public, are still described as syrups.

58- Tablets

Tablets are the most extensively used dosage forms, prepared by moulding or, usually compression.


A solid dosage form containing medicinal substances with or without diluents.

Delayed Release Tablets

A tablet with coating that is intended to postpone release of the medication until the tablet has passed through the stomach.

Extended Release Tablets

A tablet that is formulated to so as to make the contained medication available over an extended period following indigestion, extended period ranges from 8-12 hrs.

59- Transdermal Drug Delivery System(TDDS)

A self contained discrete dosage form i.e. designed to deliver drug through the intact skin to the systemic circulation.

60- Transdermal Delivery System, Electroporation

A TDS enhanced by the application of short, high voltage electric pulses to create aqueous pores in the lipid bilayer of skin and thereby facilitate drug diffusion.

61- Transdermal Delivery System, High velocity Powder Particles

A TDDS using supersonic shock waves of helium gas to increase drug diffusion through skin.

62- Transdermal Delivery System, Ionotophoresis

A TDDS enhanced by the use of applied electric current to facilitate drug diffusion through skin.

63- Transdermal Delivery System, Phonophoresis

A TDDS enhanced by the application of low frequency ultrasound to facilitate drug diffusion through skin.

64- Transdermal Matrix Patch

A transdermal matrix system using a polymeric matrix containing drug intended for systemic delivery through the skin, generally the skin is the rate controlling membrane for drug diffusion.

65- Transdermal Membrane Patch

A transdermal system containing a drug reservoir entrapped between backing and adhesive layers and a drug diffusion controlling membrane; the reservoir is usually a semisolid dispersionor solution of the drug.

66- Vitrellae

Vitrellae are thin walled glass capsules containing a volatile ingredient (e.g. amyl or octyl nitrite) and protected by absorbent cotton wool and an outer silk bag. For use, in the treatment of angina, the capsule is crushed and the vapour inhaled.

67- Urethral

A dosage form intended for insertion into the urethra to provide a local effect of the active ingredient.

Pharmaceutical Preparations Used In Extemporaneous Dispensing

The brief descriptions that follow are intended to be useful during the early weeks of a dispensing course.


Extracts are concentrated preparations containing the active principles of vegetable or animal drugs. The drugs are extracted with suitable solvents and the product is concentrated to one of three types of extract-

Liquid, of which I ml usually contains the active constituents from 1 g of drug.

Dry, obtained by completely removing the solvent under reduced pressure.

Soft, obtained by evaporation to a plastic mass.


These are solutions of medicaments in glycerol with or without the addition of water.


Fresh infusions made by extracting vegetable drugs for a short time with cold or boiling water (the making of tea) are no longer used because they quickly deteriorate as a result of microbial contamination and, therefore must be used within twelve hours of preparation. They have been replaced by concentrated infusions which are made by cold extractions with 25% alcohol; the alcohol preserves the products indefinitely. Dilution of one part to ten parts with water gives a preparation resembling the corresponding fresh infusion.


These are preparations in which the vehicle is a mixture of acid(acetic) and honey.


spirits are alcoholic or aqueous alcoholic solutions of volatile substances prepared usually by simple solution or by admixture of ingredients. Most are used as flavouring agents but a few have medicinal value.


These are alcoholic preparations containing the active principle of vegetable drugs. They are relatively weak compared with extracts.


Aromatic waters are dilute, usually saturated, solutions of volatile oils or other volatile substances (chloroform and camphor). They are mainly used as flavouring agents